Bradley Lowery, the Sunderland football mascot whose battle with a rare cancer helped raise more than £1m to help others, has died, his family said.

The six-year-old Sunderland fan came to public attention after he struck up a friendship with the club’s star striker Jermain Defoe following his diagnosis with neuroblastoma.

In a statement on the family’s Facebook page, Bradley’s mother, Gemma Lowery, said he died on Friday afternoon in his parents’ arms. “He was our little superhero and put the biggest fight up but he was needed elsewhere,” she wrote. “There are no words to describe how heartbroken we are.”

Bradley and Defoe were pictured together at the boy’s home in Blackhall, County Durham, last week after the little boy had a party in bed as a way of saying goodbye.

As Bradley continued to fight for life, Defoe broke down in tears on Thursday at a press conference with his new club, Bournemouth, when he was asked about their special bond.

The Premier League star said: “There is not a day that goes past where I do not wake up in the morning and check my phone or think about little Bradley because his love is genuine and I can see it in his eyes. It is special.”

Bradley was a mascot for Sunderland several times last season and found a place in the hearts of thousands of football fans around the world. Supporters of different clubs made banners and chanted his name at games.

He was an England mascot at a World Cup qualifier at Wembley when Defoe scored on his return to the Three Lions side. And Defoe was guest of honour at a huge party thrown for Bradley’s sixth birthday in May.

Supporters had hoped a massive fundraising effort last year could get him to the US for pioneering treatment, but his heartbroken family announced at Christmas that his cancer was terminal.

They kept his many well-wishers around the world up to date by using social media and in his final days, Gemma revealed that Bradley’s health was deteriorating quickly.